<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>tf::Future class | Taskflow QuickStart</title>
  <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:400,400i,600,600i%7CSource+Code+Pro:400,400i,600" />
  <link rel="stylesheet" href="m-dark+documentation.compiled.css" />
  <link rel="icon" href="favicon.ico" type="image/x-icon" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <meta name="theme-color" content="#22272e" />
</head>
<body>
<header><nav id="navigation">
  <div class="m-container">
    <div class="m-row">
      <span id="m-navbar-brand" class="m-col-t-8 m-col-m-none m-left-m">
        <a href="https://taskflow.github.io"><img src="taskflow_logo.png" alt="" />Taskflow</a> <span class="m-breadcrumb">|</span> <a href="index.html" class="m-thin">QuickStart</a>
      </span>
      <div class="m-col-t-4 m-hide-m m-text-right m-nopadr">
        <a href="#search" class="m-doc-search-icon" title="Search" onclick="return showSearch()"><svg style="height: 0.9rem;" viewBox="0 0 16 16">
          <path id="m-doc-search-icon-path" d="m6 0c-3.31 0-6 2.69-6 6 0 3.31 2.69 6 6 6 1.49 0 2.85-0.541 3.89-1.44-0.0164 0.338 0.147 0.759 0.5 1.15l3.22 3.79c0.552 0.614 1.45 0.665 2 0.115 0.55-0.55 0.499-1.45-0.115-2l-3.79-3.22c-0.392-0.353-0.812-0.515-1.15-0.5 0.895-1.05 1.44-2.41 1.44-3.89 0-3.31-2.69-6-6-6zm0 1.56a4.44 4.44 0 0 1 4.44 4.44 4.44 4.44 0 0 1-4.44 4.44 4.44 4.44 0 0 1-4.44-4.44 4.44 4.44 0 0 1 4.44-4.44z"/>
        </svg></a>
        <a id="m-navbar-show" href="#navigation" title="Show navigation"></a>
        <a id="m-navbar-hide" href="#" title="Hide navigation"></a>
      </div>
      <div id="m-navbar-collapse" class="m-col-t-12 m-show-m m-col-m-none m-right-m">
        <div class="m-row">
          <ol class="m-col-t-6 m-col-m-none">
            <li><a href="pages.html">Handbook</a></li>
            <li><a href="namespaces.html">Namespaces</a></li>
          </ol>
          <ol class="m-col-t-6 m-col-m-none" start="3">
            <li><a href="annotated.html">Classes</a></li>
            <li><a href="files.html">Files</a></li>
            <li class="m-show-m"><a href="#search" class="m-doc-search-icon" title="Search" onclick="return showSearch()"><svg style="height: 0.9rem;" viewBox="0 0 16 16">
              <use href="#m-doc-search-icon-path" />
            </svg></a></li>
          </ol>
        </div>
      </div>
    </div>
  </div>
</nav></header>
<main><article>
  <div class="m-container m-container-inflatable">
    <div class="m-row">
      <div class="m-col-l-10 m-push-l-1">
        <h1>
          <div class="m-doc-template">template&lt;typename T&gt;</div>
          <span class="m-breadcrumb"><a href="namespacetf.html">tf</a>::<wbr/></span>Future <span class="m-thin">class</span>
        </h1>
        <p>class to access the result of an execution</p>
        <nav class="m-block m-default">
          <h3>Contents</h3>
          <ul>
            <li>
              Reference
              <ul>
                <li><a href="#typeless-methods">Constructors, destructors, conversion operators</a></li>
                <li><a href="#pub-methods">Public functions</a></li>
              </ul>
            </li>
          </ul>
        </nav>
<p><a href="classtf_1_1Future.html" class="m-doc">tf::<wbr />Future</a> is a derived class from <a href="http://en.cppreference.com/w/cpp/thread/future.html" class="m-doc-external">std::<wbr />future</a> that will eventually hold the execution result of a submitted taskflow (tf::Executor::run) In addition to the base methods inherited from <a href="http://en.cppreference.com/w/cpp/thread/future.html" class="m-doc-external">std::<wbr />future</a>, you can call <a href="classtf_1_1Future.html#a3bf5f104864ab2590b6409712d3a469b" class="m-doc">tf::<wbr />Future::<wbr />cancel</a> to cancel the execution of the running taskflow associated with this future object. The following example cancels a submission of a taskflow that contains 1000 tasks each running one second.</p><pre class="m-code"><span class="n">tf</span><span class="o">::</span><span class="n">Executor</span><span class="w"> </span><span class="n">executor</span><span class="p">;</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Taskflow</span><span class="w"> </span><span class="n">taskflow</span><span class="p">;</span>

<span class="k">for</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="o">=</span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">&lt;</span><span class="mi">1000</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w">  </span><span class="n">taskflow</span><span class="p">.</span><span class="n">emplace</span><span class="p">([](){</span>
<span class="w">    </span><span class="n">std</span><span class="o">::</span><span class="n">this_thread</span><span class="o">::</span><span class="n">sleep_for</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">chrono</span><span class="o">::</span><span class="n">seconds</span><span class="p">(</span><span class="mi">1</span><span class="p">));</span>
<span class="w">  </span><span class="p">});</span>
<span class="p">}</span>

<span class="c1">// submit the taskflow</span>
<span class="n">tf</span><span class="o">::</span><span class="n">Future</span><span class="w"> </span><span class="n">fu</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">executor</span><span class="p">.</span><span class="n">run</span><span class="p">(</span><span class="n">taskflow</span><span class="p">);</span>

<span class="c1">// request to cancel the submitted execution above</span>
<span class="n">fu</span><span class="p">.</span><span class="n">cancel</span><span class="p">();</span>

<span class="c1">// wait until the cancellation finishes</span>
<span class="n">fu</span><span class="p">.</span><span class="n">get</span><span class="p">();</span></pre>
        <section id="typeless-methods">
          <h2><a href="#typeless-methods">Constructors, destructors, conversion operators</a></h2>
          <dl class="m-doc">
            <dt id="a520785365a129094d7ecf11e217509db">
              <span class="m-doc-wrap-bumper"><a href="#a520785365a129094d7ecf11e217509db" class="m-doc-self">Future</a>(</span><span class="m-doc-wrap">) <span class="m-label m-flat m-info">defaulted</span></span>
            </dt>
            <dd>default constructor</dd>
            <dt id="ad22645f2bcbd2af449cfcd36eace9a1b">
              <span class="m-doc-wrap-bumper"><a href="#ad22645f2bcbd2af449cfcd36eace9a1b" class="m-doc-self">Future</a>(</span><span class="m-doc-wrap">const <a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp;) <span class="m-label m-flat m-danger">deleted</span></span>
            </dt>
            <dd>disabled copy constructor</dd>
            <dt id="ae6c5f935a2062f58054b067d39f5e78a">
              <span class="m-doc-wrap-bumper"><a href="#ae6c5f935a2062f58054b067d39f5e78a" class="m-doc-self">Future</a>(</span><span class="m-doc-wrap"><a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp;&amp;) <span class="m-label m-flat m-info">defaulted</span></span>
            </dt>
            <dd>default move constructor</dd>
          </dl>
        </section>
        <section id="pub-methods">
          <h2><a href="#pub-methods">Public functions</a></h2>
          <dl class="m-doc">
            <dt id="a5203e9c97fad413b67f6f8ba1d322782">
              <span class="m-doc-wrap-bumper">auto <a href="#a5203e9c97fad413b67f6f8ba1d322782" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap">const <a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp;) -&gt; <a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp; <span class="m-label m-flat m-danger">deleted</span></span>
            </dt>
            <dd>disabled copy assignment</dd>
            <dt id="a52777516391d8c799ac93830fc47402a">
              <span class="m-doc-wrap-bumper">auto <a href="#a52777516391d8c799ac93830fc47402a" class="m-doc-self">operator=</a>(</span><span class="m-doc-wrap"><a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp;&amp;) -&gt; <a href="classtf_1_1Future.html" class="m-doc">Future</a>&amp; <span class="m-label m-flat m-info">defaulted</span></span>
            </dt>
            <dd>default move assignment</dd>
            <dt>
              <span class="m-doc-wrap-bumper">auto <a href="#a3bf5f104864ab2590b6409712d3a469b" class="m-doc">cancel</a>(</span><span class="m-doc-wrap">) -&gt; bool</span>
            </dt>
            <dd>cancels the execution of the running taskflow associated with this future object</dd>
          </dl>
        </section>
        <section>
          <h2>Function documentation</h2>
          <section class="m-doc-details" id="a3bf5f104864ab2590b6409712d3a469b"><div>
            <h3>
              <div class="m-doc-template">
                template&lt;typename T&gt;
              </div>
              <span class="m-doc-wrap-bumper">bool tf::<wbr />Future&lt;T&gt;::<wbr /></span><span class="m-doc-wrap"><span class="m-doc-wrap-bumper"><a href="#a3bf5f104864ab2590b6409712d3a469b" class="m-doc-self">cancel</a>(</span><span class="m-doc-wrap">)</span></span>
            </h3>
            <p>cancels the execution of the running taskflow associated with this future object</p>
            <table class="m-table m-fullwidth m-flat">
              <tfoot>
                <tr>
                  <th style="width: 1%">Returns</th>
                  <td><code>true</code> if the execution can be cancelled or <code>false</code> if the execution has already completed</td>
                </tr>
              </tfoot>
            </table>
<p>When you request a cancellation, the executor will stop scheduling any tasks onwards. Tasks that are already running will continue to finish (non-preemptive). You can call tf::Future::wait to wait for the cancellation to complete.</p>
          </div></section>
        </section>
      </div>
    </div>
  </div>
</article></main>
<div class="m-doc-search" id="search">
  <a href="#!" onclick="return hideSearch()"></a>
  <div class="m-container">
    <div class="m-row">
      <div class="m-col-m-8 m-push-m-2">
        <div class="m-doc-search-header m-text m-small">
          <div><span class="m-label m-default">Tab</span> / <span class="m-label m-default">T</span> to search, <span class="m-label m-default">Esc</span> to close</div>
          <div id="search-symbolcount">&hellip;</div>
        </div>
        <div class="m-doc-search-content">
          <form>
            <input type="search" name="q" id="search-input" placeholder="Loading &hellip;" disabled="disabled" autofocus="autofocus" autocomplete="off" spellcheck="false" />
          </form>
          <noscript class="m-text m-danger m-text-center">Unlike everything else in the docs, the search functionality <em>requires</em> JavaScript.</noscript>
          <div id="search-help" class="m-text m-dim m-text-center">
            <p class="m-noindent">Search for symbols, directories, files, pages or
            modules. You can omit any prefix from the symbol or file path; adding a
            <code>:</code> or <code>/</code> suffix lists all members of given symbol or
            directory.</p>
            <p class="m-noindent">Use <span class="m-label m-dim">&darr;</span>
            / <span class="m-label m-dim">&uarr;</span> to navigate through the list,
            <span class="m-label m-dim">Enter</span> to go.
            <span class="m-label m-dim">Tab</span> autocompletes common prefix, you can
            copy a link to the result using <span class="m-label m-dim">⌘</span>
            <span class="m-label m-dim">L</span> while <span class="m-label m-dim">⌘</span>
            <span class="m-label m-dim">M</span> produces a Markdown link.</p>
          </div>
          <div id="search-notfound" class="m-text m-warning m-text-center">Sorry, nothing was found.</div>
          <ul id="search-results"></ul>
        </div>
      </div>
    </div>
  </div>
</div>
<script src="search-v2.js"></script>
<script src="searchdata-v2.js" async="async"></script>
<footer><nav>
  <div class="m-container">
    <div class="m-row">
      <div class="m-col-l-10 m-push-l-1">
        <p>Taskflow handbook is part of the <a href="https://taskflow.github.io">Taskflow project</a>, copyright © <a href="https://tsung-wei-huang.github.io/">Dr. Tsung-Wei Huang</a>, 2018&ndash;2024.<br />Generated by <a href="https://doxygen.org/">Doxygen</a> 1.9.6 and <a href="https://mcss.mosra.cz/">m.css</a>.</p>
      </div>
    </div>
  </div>
</nav></footer>
</body>
</html>
